Pavement and method of manufacturing the same



Jan. 3, 1928. 1,654,746

1 C. A. MULLEN' PAVEMENT AND METHOD OF MANUFACTURING THE SAME Filed Feb. 9, 1925 WWW Patented Jan. 3, 1928.

Om AUGUSTINE MULLER, OI MONTREAL, QUEBEC, CANADA.

ravmmn'r am) ma'rnon or MANUFACTURING m sum.

Application filed February 9, 1935, Serial No. 7,878, and in Canada January 5, 1925.

This invention relates to improvements in pavement and method of manufacturmg the same, and in general my invention relates to that type of pavement which is constructed 6 of two or more layers of mixture, each of which mixture consists of intermlngled, irregular shaped rigid mineral or other particles, such as crushed stone, gravel, slag, I sand, dust, known as the aggregate, coated 10 and cemented together by a 'plastlc material,

such as asphalt, tar, oil, known as the ce-- menting medium, in which type of pavement.

such a layer of mixture is spread and compressed, while sufiiciently plastlc, upon another such layer of mixture which previously has been spread, or spread and compressed.

In particular my invention relates to that typeof pavement which is constructed of two or more layers of mixtures, each. of which mixtures consists of intermingled irregular sha ed rigid mineral or ot er particles, WhlCh particles, known as the mineral aggregate, are graded from some-maximum as size down to a very small size so that, when intenmingled and coated and cemented to-' ment by spreading one mixture as an upper layer upon another such mixture as a lower layer without previously compressing the under layer and then compressin layers at once, while they are still su ciently plastic. I

It has also been heretofore proposed to secure an interlocking between two such layers of mixture by spreading one such l0 mixture asan upper layer upon another such mixture as a lower layer, after previously compressing the under layer only enough to turn down the points'of the larger particles that protrude from the surface and then sed to secure both pression of the under layer immediately after it is spread.

The purpose of my invention is to secure a uniform predetermined form of interlock- 7 ing of such upper and under layers instead of the haphazard interlocking provided by the accidents of spreading, and to. permit the sufiicientcompression of the under layer immediately after it is spread, thus avoiding any lack of uniformity of compression due 'to occasional delays in spreading the upper layer and the consequent stiffening of the under layer, 'by cooling or otherwise, before the two layers are compressed together.

My invention consists in a pavement, and

in the process of producing that. avement by which I secure a predetermine form 0 interlocking between such an upper layer and such an under layer by impressing upon the under layer, while it is still sufficiently plastic, a pattern of raised or lowered sections or points, so that when the upper layer is spread and compressed upon the under layer, the said upper la er will engage the said under layer, in the orm of interlocking predetermined by the pattern.

The angles of the pattern may be so arranged as to lgive a form of interlocking which offers t e greatest resistance to the displacement of'the upper layer on the under layer by the thrust of" traflic. The pattern may be applied by means of a special roller carrying the pattern on its circumference, which rollers may be moved "from curb to curb, or diagonally or lengthwise, over the under layer, after it is spread, and while sufliciently. plastic; or the pattern may be applied by means of a special tamper carrying the pattern on its face; or,

1 the pattern may be a plied by means of a special belt carrying t e pattern on one side, which belt may be placed over the under layer, after it is spread, and while sufiiciently plastic, and the pattern on the belt imprinted on the said under layer by means of a plain tamper applied to the u per side of the belt, or by any other suitabib means.

When the mixture of the under la or is one having a coarse aggregate, and t atof the layer immediately above is one having a fine aggregate, the pattern may be so desi ed asto take advantage of the coarse particles of the mixtures of the under layer so as to arrange some of thesecoarse particles as somewhat uniformly spaced and levelled projections between whichthe finer aggregate of the mixture in the layer im- S1011 into corresponding mediately above will be present and interlocked, by being formed, through compres ly unifo y arranged rojections into the layer immediatel ow.

0 two layers which are interlocked may each receive final compression separately; or the under layer may either receive but the light compression'incident. to the impressing of the pattern, or it may receive any degreeof artial compression that may be considered esirable, before the la or immediately above is s read and e two interlocking layers fin compressed together, while both are st'l suificiently plastic. v

In the attached drawings:

Figure 1 is a sectional view of a pavement embodying the present invention, and

Fi es 2, 3, and 4. are dis onal views showing forms of patterns which may be impressed upon the lower layer.

' Referring to Figure 1, 10 indicates the; to surface of any suitable foundation. A

in 'cates the under layer mixture, com-,

p llpssed in place between the, lines 10 and 11.

e line 11 represents the impression of, the.

pattern upon the under layer mixture, which oint may be of any suitable or convenient.

design, such for instance as the cross corrugations indicated in Figure 2, the diagonal corrugations indicatedin Figure 3, and the parallel cross corrugations indicated in Figure 4.

B indicates the upper layer mixture compressed in place between the line 11 and the line12 the form of its interlocking with the lower layer A being governed by the impression of the pattern at 11. 12 represents the line of the to surface of the upper later mixture, which i desired maybe given any suitable surface treatment,

It will be seen that, according to the present invention, the form of interlocking is regulated by a definitely determined pattern and does not necessitate leavin the under layer uncompressed. or only slightly compressed until after the upper layer is spread. It may be observed t at the compression of both upper and lower layers of the. pavement may be varied to suit varied conditions.

For instance, the compression of the underlayer, prior to the spreading of the upper layer may only be suflicient to form the' 7 pattern on the top of the under layer, the

al compression of both layers bein effected simultaneously after the upper ayer has been spread and while both layers are sufficiently plastic..

The di ofthea e eof. eachlayer may be fiiadh to suit finection of the material in. handand the condition of traflic. In use I find it preferable, in .the upper layer, to grade the mineral egate from aboutone-tenth'to one-quarter inch size down and in the under layer tograde the mineral aggregate. fromabout one toone and one-' half inch size down.

The pattern may be conveniently designed to take advantagelof the coarse particles of the under layer so as to an some of these coarse as somewhatuniformly' spaced and levelled projections between which the finer to in the layer immediately above will presed and interlocked by being formed through compression into corresponding uniformly ar ranged' projec-.

tions into the yer below.

It will be observed in Figure 1 of the drawings certain of the coarser particles of the lower layer project upwardly in this manner.

As many changes could be made in the above construction and many apparently widely different embodiments of my invention within the scope of the claims-noon bituminous plastic material, then impressing upon said mixture constituting the lower layer, while sufficiently plastic, a regular pattern of raised and lowered sections or points,

then spreading an upper finer layer upon said lower layer, said upper layer consisting of previously mixed intermin led irregular shaped rigid mineral or 0t er particles coated and cementedtogether by a bituminous plastic material. 1

2.. The herein described. pavement comprising a coarser lower layer of intermingled irregular shaped rigid mineral or other particles coated and cemented together by abituminous plastic material, and having impressed thereon while sufiiciently plastic, a regular pattern of raised and lower d seetions, or points, an upper finer laye upon 1 said lower layer, said upper layereonsisting of previously mixed intermingled irregular shaped rigid mineral or other particles coated and cemented together by a bitumi nous lasticmaterial.

3. e pavement as claimed in claim 2, in

which the mineral aggregate of the upper layer is graded from about one-tenth to onequarter inch size down and the mineral aggregate of the under layer is graded from about three-quarters to one and one-half inch size down.

4. The pavement as claimed in claim 2, in which the lower layer is provided with coarse particles which, when the Pattern is impressed on the lower layer, are arranged to project upwardly into suitable portions of the-pattern.

5. The method as claimed in claim 1, in

whichthe upper and lower layers are finally compressed together.

6. The pavement as claimed in claim 2, in which the pattern includes parallel corrugations.

7. The pavement as claimed in claim 2, in which the attern includes diagonally extending parallel corru tions.

In witness whereof I have hereunto setmy hand.

CHARLES AUGUSTINE ULLEN, 

